CD and /sup 1/H NMR studies of native hemeproteins and hemeproteins containing modified hemes
Many of the experiments presented in this thesis were designed in an attempt to assess the contribution(s), if any, of heme distortion (i.e. 2,4 vinyl group twisting and porphyrin core deformation) to the CD spectra of hemeproteins. Myoglobin, hemoglobin and cytochrome c peroxidase were reconstituted with hemes modified at the 2,4 positions and the CD spectra of these samples were recorded in order to measure the extent to which the 2,4 vinyl groups of the heme contribute to the optically active heme transitions. The /sup 1/H NMR spectra of the cyanide liganded forms of these protein derivatives were also recorded for the purpose of determining the orientation of the reconstituted heme in the protein heme pocket, since two heme orientations differing by a 180/sup 0/ rotation about the heme ..cap alpha..-..gamma.. meso axis are possible in reconstituted hemeproteins (i.e. heme scrambling). Relatively minor spectral changes occur in the Soret CD spectra of the hemeproteins reconstituted with mesohemin (2,4 = ethyl) indicating that the ..pi.. electrons of the vinyl groups of native protohemin do not contribute substantially to the optically active heme transitions. The studies on cytochrome c peroxidase (CCP) containing hemes modified at the 2,4 positions indicate that the CD spectra of these protein derivatives are remarkably similar. Such an observation may be related to the fact that modification of the heme 2,4 substituents does not alter the activity of CCP.
- Research Organization:
- Colorado State Univ., Fort Collins (USA)
- OSTI ID:
- 6354185
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
BARYONS
CARBOXYLIC ACIDS
CONFORMATIONAL CHANGES
DICHROISM
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
GLOBIN
HADRONS
HEME
HEMOGLOBIN
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MAGNETIC RESONANCE
MYOGLOBIN
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDOREDUCTASES
PEROXIDASES
PIGMENTS
PORPHYRINS
PROTEINS
PROTONS
RESONANCE
SPECTRA
STEREOCHEMISTRY